Many bag-filling machines have been devised and for many different styles of bags. A prior art machine has been constructed for filling pinch bottom paper bags, either lined or unlined bags, but the speed has been quite slow. Also, with the larger sizes of bags, especially in the pinch-bottom style of paper bag, the height of the bag is not completely uniform from one bag to the next. The prior art system has been to align the top edge of the bag relative to the filling mechanism by gripping the top edge of the bag with the bag oriented by resting on the bottom edge. It has now been found that the height of the bag might vary as much as 0.25 inches (0.635 cm.), and this made the gripping of the openable top edge of the bag vary by as much as this amount of 0.25 inches.
Recently, there has been an increased emphasis on tightly sealing these pinch-bottom bags, especially when finely powdered material such as portland cement is being packaged. Another critical use is in the packaging of food stuffs such as flour which is to be shipped overseas. The pinch-bottom type of bag may have a band of adhesive, for example, 1.5 inches (3.82 cms.) applied along one inner face near the openable edge. After filling this adhesive covered face is turned down a certain amount, e.g., 1.0 inches (2.54 cms.) and sealed. This may be accomplished by heating if it is a heat-sealable adhesive. If the bag varies by as much as 0.25 inches in height, then this means that folding over a flap on the top edge this flap might be 1.0 inches or it might be 1.25 inches (3.18 cms.). This much of a variation in the width of the flap can mean a failure to completely seal the contents within the bag. If the folded-over flap is too narrow or if it is too wide, then leakage can occur at the two ends of the flap. Not only can leakage occur, but vermin seem to be able to enter even the tiniest crevice. Accordingly, for bags to contain foodstuffs such as flour, the proper aligning of the openable top edge of the bag is extremely important.
Accordingly, this problem is solved according to the present invention by providing a bag-aligner machine which aligns an edge of a bag by actually locating the openable edge of the bag rather than attempting to determine where that edge of the bag might be from the opposite end of the bag.
An object of the invention is to provide a bag-aligner machine which obviates the above-mentioned disadvantages.
Another object of the invention is to provide a bag-aligner machine wherein a bag holder moves an edge of a bag into the open end of a V configuration of first and second alignment members until the edge of the bag abuts closed V end.
Another object of the invention is to provide a bag edge locator for a pinch-bottom bag so that the openable edge of the bag may be properly gripped, opened and filled and then folded and sealed so that the sealing is proper and prevents leakage of the contents from the bag.
Another object of the invention is to provide a bag-aligner machine wherein a first motor and resilient means moves a bag holder holding the bag so that an edge of the bag is moved into the open V-end between first and second alignment members to abut the closed V-end under the urging of the resilient means.